AUSTIN (KXAN) — Dense breast tissue has been associated with a 1.2 to four times higher risk of breast cancer, depending on the degree of density. Despite it being a significant risk factor for developing the most common cancer in women (about one and eight women get breast cancer), a new study published in Jama Network Open found that many women were unaware of the connection. 

Researchers on this project surveyed 1858 women between the ages of 40 to 76 who had recently undergone a mammogram and had heard of breast density. The study participants were asked to compare the risk associated with breast density with five other breast cancer risk factors – including significant family history, alcohol consumption, parity and having had a prior breast biopsy. 

A woman with significant family history – for example, having a mother or sister who had breast cancer – is associated with a two times higher risk of developing breast cancer. 

The researchers found that nearly 95% of the respondents incorrectly perceived family history as the greatest risk factor for developing breast cancer. Further, they found that respondents thought if they did not have a strong family history of breast cancer, then they were safe or had a limited risk of developing cancer, the study’s authors wrote. 

Also, one-third of the women thought they could not take any actions to reduce their breast cancer risk. The Mayo Clinic said a woman could reduce her risk for breast cancer by limiting alcohol, maintaining a healthy weight, exercising, breastfeeding and limiting post-menopausal hormone therapy.

Breast Density

A breast is considered to be denser if it has more fibrous and granular tissue – the part of the breast that produces milk – than fatty tissue. Many women may find out they have dense breast tissue after their first mammogram. 

Dr. Brett Deathridge, a radiologist with Ascension Medical Center, said that medical professionals categorize breasts into four different groups. The categories range from breasts composed almost entirely of fat cells to breasts extremely dense with granular tissue. Breast cancer risk increases with the density of the breast, but Deathridge said doctors are not entirely certain why. 

“It seems that the more breast tissue that there is, the more chances that there can be some kind of alteration at a cellular level and [increases] the risk of breast cancer. So just having more breast tissue, [then] allows for more chances for abnormal tissue and then breast cancer to develop,” Deathridge said. 

Currently, 38 states – including Texas – and the District of Colombia require some form of breast density notification following a mammogram so women can be aware of their risk. The study authors wrote that despite these laws, women still did not describe a strong understanding of the risk associated with breast density relative to other breast cancer risk factors.

Deathridge said it was exceedingly important for people to be aware of their risk level. If a woman meets the criteria for having multiple risk factors, it may be recommended she start getting screened at a younger age than typical or undergo supplemental screenings. The current recommendation for an average-risk woman is to get screened for breast cancer at 40. 

“If you have a high enough risk, you may need supplemental breast screening before the age of 40,” he said. 

For women with dense breast tissue, mammograms are not the best imaging modality to detect breast cancer. Deathridge said there is also tomosynthesis – a more advanced form of mammogram – that allows medical professionals to see multiple layers of the breast, unlike in a typical mammogram. 

Further, Deathridge said that if a woman’s risk level is elevated, she can also have an MRI screening, which is known to be the most effective imaging technique in detecting breast cancer. If a woman has an advanced risk, Deathridge said most medical insurance companies would cover these supplemental screenings. 

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“Whenever you have a new complaint – whether you feel a lump, a mass or pain – It’s important to speak with your doctor and to have breast imaging as necessary,” Deathridge said. “It’s also important to know your individual risk of breast cancer based on your breast density, your family history and other risk factors.”